Field of the Disclosure
The disclosure relates to a gas furnace that heats an indoor space by supplying warm air via heat exchange between internal air and hot exhaustion gas generated by combustion of fuel, and a controlling method thereof. More particularly, the disclosure relates to a gas furnace for heating an indoor space including one valve of which a heating power is controllable by multi-steps, and a controlling method thereof.
Discussion of the Related Art
In general, a gas furnace is a device used for heating an indoor space.
A gas furnace generally includes a burner for fuel combustion. The gas furnace provides heat by adjusting the amount of the fuels supplied to the burner. In other words, the controlling of the heating is the controlling of the heating intensity. The amount of fuel supplied to the burner is controlled by a valve. Typically, the supply and shut-off of fuels may be controlled by using a solenoid valve which is an on/off controllable valve.
For example, FIG. 1 schematically illustrates a fuel supply unit including a conventional valve for controlling the amount of the fuel supplied to the burner. Referring to FIG. 1, the fuel supply unit 1 includes a fuel line 3 for supplying fuel to the burner 2 and two solenoid valves 4-1 and 4-2 provided in the fuel line 3. The two solenoid valves 4-1 and 4-2 may include a first solenoid valve 4-1 and a second solenoid valve 4-2. The first solenoid valve 4-1 may be arranged in a front portion with respect to fuel flow, compared with the second solenoid valve 42.
When receiving no signal from a controller (not shown), the first solenoid 4-1 is maintained in an initial closed state and the second solenoid valve 4-2 is maintained in an initial state in which it partially opens the fuel line 3. At this time, the fuel is not supplied to the burner 2.
The controller may control ON and OFF of the first and second solenoid valves 4-1 and 4-2 based on a signal transmitted from a thermostat (not shown) searched in the indoor space.
When receiving a middle heat-power signal from the controller, the first solenoid valve 4-1 is completely open and the second solenoid valve 4-2 maintains the initial state in which it has partially opened the fuel line 3.
When receiving a high heat-power level signal from the controller, the first solenoid valve 4-1 and the second solenoid valve 4-2 are completely open.
As mentioned above, the conventional gas furnace is able to control the heat power of the burner 2 via two levels, based on the two signals transmitted by the thermostat and the ON/OFF control of the two solenoid valves 4-1 and 4-2.
Meanwhile, the conventional gas furnace uses the thermostat generating the two signals and the two solenoid valves 4-1 and 4-2, so that it has a disadvantage of incapability of controlling the heat power of the burner 2 by three or more difference heat force (in other words, heating intensities).
In addition, the conventional gas furnace uses two or more solenoid valves 4-1 and 4-2 to control two or more heat powers and cannot help requiring the securing of the installation space for installing the plurality of the valves and having the complex flow path disadvantageously.
The conventional gas furnace is incapable of controlling the heat power linearly and has the complex flow path for the fuel supply, only to have a relatively high production cost.
Lastly, the conventional gas furnace is capable of controlling only the two steps of heat power based on the two signals transmitted from the thermostat, only to have a disadvantage of a large temperature difference in the indoor space.